Ice Breaking Drilling Vessel With Stowable Mast

Abstract

A drilling vessel may function both as an ice breaker and, if needed, as a drilling platform for drilling a relief well. The vessel may be provided with a mast that may be stowed when drilling operations are not being conducted.

1 . A method comprising:
 providing a drilling vessel with an ice breaking hull and a stowable drilling mast.   
     
     
         2 . The method of  claim 1  including providing a pivoting mast. 
     
     
         3 . The method of  claim 1  including providing a telescoping mast. 
     
     
         4 . The method of  claim 1  including providing a telescoping and pivoting mast. 
     
     
         5 . The method of  claim 1  including using said vessel to break ice and to stand by to drill a relief well if needed. 
     
     
         6 . The method of  claim 1  including enabling the mast to be stowed entirely below deck. 
     
     
         7 . The method of  claim 1  including providing a lower mast portion for telescoping extension and an upper mast portion connected to the lower mast portion for pivoting extension. 
     
     
         8 . A drilling vessel comprising:
 an ice breaking hull; and   a stowable drilling mast.   
     
     
         9 . The vessel of  claim 8  including a two-part mast, and a pivoting connection between said parts. 
     
     
         10 . The vessel of  claim 9  wherein one part is mounted on the other part, the one part mounted to pivot on the other part. 
     
     
         11 . The vessel of  claim 10  wherein the other part is mounted for upward telescoping extension. 
     
     
         12 . The vessel of  claim 8  including a two-part telescoping mast. 
     
     
         13 . The vessel of  claim 8  including a deck wherein said mast is entirely stowable below said deck. 
     
     
         14 . A mast for a drilling vessel comprising:
 a first telescoping portion;   a second telescoping portion extendable from within said first telescoping portion to an elongated configuration; and   a mounting to support said second telescoping portion within a ship's hull.   
     
     
         15 . The mast of  claim 14  wherein said portions are mounted over a third portion for relative pivotal motion. 
     
     
         16 . The mast of  claim 14  said mast including at least three extendable portions. 
     
     
         17 . The mast of  claim 14  said mounting to mount said mast under a ship's deck.